For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim's website at www.maxim-ic.com.

General Description

The MAX8640Y/MAX8640Z step-down converters are

optimized for applications where small size, high effi-

ciency, and low output ripple are priorities. They utilize

a proprietary PWM control scheme that optimizes the

switching frequency for high efficiency with small exter-

nal components and maintains low output ripple volt-

age at all loads. The MAX8640Z switches at up to

4MHz to allow a tiny 1µH inductor and 2.2µF output

capacitor. The MAX8640Y switches at up to 2MHz for

higher efficiency while still allowing small 2.2µH and

4.7µF components. Output current is guaranteed up to

500mA, while typical quiescent current is 28µA.

Factory-preset output voltages from 0.8V to 2.5V elimi-

nate external feedback components.

Internal synchronous rectification greatly improves effi-

ciency and replaces the external Schottky diode

required in conventional step-down converters. Internal

fast soft-start eliminates inrush current so as to reduce

input capacitor requirements.

The MAX8640Y/MAX8640Z are available in the tiny 6-

pin, SC70 (2.0mm x 2.1mm) and µDFN (1.5mm x

1.0mm) packages. Both packages are lead-free.

Applications

Microprocessor/DSP Core Power

I/O Power

Cell Phones, PDAs, DSCs, MP3s

Other Handhelds Where Space Is Limited

Features

♦ Tiny SC70 and µDFN Packages

♦ 500mA Guaranteed Output Current

♦ 4MHz or 2MHz PWM Switching Frequency

♦ Tiny External Components: 1µH/2.2µF or

2.2µH/4.7µF

♦ 28µA Quiescent Current

♦ Factory Preset Outputs from 0.8V to 2.5V

♦ ±1% Initial Accuracy

♦ Low Output Ripple at All Loads

♦ Ultrasonic Skip Mode Down to 1mA Loads

♦ Ultra-Fast Line- and Load-Transient Response

♦ Fast Soft-Start Eliminates Inrush Current

Tiny 500mA, 4MHz/2MHz Synchronous

Step-Down DC-DC Converters

________________________________________________________________

Maxim Integrated Products

1

19-3997; Rev 4; 2/09

EVALUATION

KIT

AVAILABLE

Ordering Information

PART*

PIN-

PACKAGE

TOP MARK

MAX8640YEXT08+T

6 SC70

ACQ

MAX8640YEXT10+T

6 SC70

ADF

MAX8640YEXT11+T

6 SC70

ACR

MAX8640YEXT12+T

6 SC70

ACS

MAX8640YEXT13+T

6 SC70

ACG

MAX8640YEXT15+T

6 SC70

ADD

MAX8640YEXT16+T

6 SC70

ADB

MAX8640YEXT18+T

6 SC70

ACI

MAX8640YEXT19+T

6 SC70

ACH

MAX8640YEXT82+T

6 SC70

ADJ

GND

OUT

1

+

+

6

IN

5

GND

LX

GND

OUT

LX

MAX8640Y

MAX8640Z

MAX8640Y

MAX8640Z

SC70

2.0mm x 2.1mm

TOP VIEW

2

3

6

5

4

4

1

2

3

SHDN

IN

GND

SHDN

μDFN

1.5mm x 1.0mm

Pin Configurations

L1

1

μH OR 2.2μH

C2

2.2

μF OR

4.7

μF

C1

2.2

μF

OUT

LX

GND

IN

SHDN

ON/OFF

MAX8640Y

MAX8640Z

INPUT

2.7V TO 5.5V

OUTPUT

0.8V TO 2.5V

UP TO 500mA

Typical Operating Circuit

Ordering Information continued and Selector Guide appears

at end of data sheet.

*

Contact factory for availability of each version. For 2.85V output

(82 version), request application note that includes limitations

and typical operating characteristics.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

T = Tape and reel.

Note: All devices are specified over the -40°C to +85°C

operating temperature range.